1. Field of the Invention
The invention relates to a portable terminal and a portable telephone such as a 3G (third Generation mode telecommunication) terminal and so forth, particularly to a portable terminal and a portable telephone corresponding to various communication systems such a W-CDMA (Wideband-Code Division Multiple Access) system and so forth and a master slave portable telephone system.
2. Description of the Related Art
A portable terminal corresponding to a conventional communication system is configured, for example, as shown in FIG. 1. FIG. 1 shows the summary of a portable terminal. A portable terminal 2 has a radio part 4 and a control part 6 as a basic configuration. The radio part 4 in the preceding stage is a part for effecting transmission and/or reception of an RF (Radio Frequency) signal while using radio wave serving as a transmission medium, and has an antenna 8, a transmission and/or reception switching part 10, an RF (Radio Frequency) reception part 12, an RF transmission part 14, and a base band part 16. The control part 6 in the subsequent stage has a processing part 18, a microphone 20, a speaker 22, a keyboard 24, a display part 26 and so forth. The processing part 18 has a CPU (Central Processing Unit), a ROM (Read-Only Memory), a RAM (Random-Access Memory) and so forth, which execute a key board control, a voice amplification, a display control, an application control and so forth.
According to the portable terminal 2, a base band signal is demodulated from the RF signal received by the RF reception part 12, and a voice signal which is separated from the base band signal at the base band part 16 is reproduced as a voice by the speaker 22 via the processing part 18. Further, an input signal to the keyboard 24 and an input signal to the microphone 20 are converted into the base band signal by the base band part 16 via the processing part 18, and the converted base band signal is modulated at the RF transmission part 14 and is transmitted via the antenna 8 as the RF signal.
With such an arrangement of the portable terminal, the W-CDMA prevails as a future generation portable telephone system serving as a universal common portable telephone system, and a universal standard system of an IMT 2000 (International Mobile Telecommunication-2000), but the basic configuration of the portable terminal of this new communication system is the same as the configuration shown in FIG. 1. However, the portable telephone system of the new communication system mounts thereon a hardware and a software for realizing a high capacity data communication, a high image quality display, a high grade sound quality, thereby enhancing high-function compared with the portable telephone system of the conventional communication system.
There exists, for example, a patent document such as JP-A 2002-9689 disclosing the portable telephone relating to the W-CDMA.
JP-A 2002-9689 relates to a portable telephone for effecting communication by the W-CDMA system, and it plans to realize a portable telephone capable of more precisely specify a long code even under the influence of phasing.
Meanwhile, the portable terminal of the new communication system such as high-function W-CDMA and so forth is developing in respect of downsizing and low power consumption compared with the portable terminal of the existing communication system. That is, it makes the portable terminal difficult to be downsized and to be low in power consumption because downsizing and low power consumption of core components of the radio part 4 are insufficient and also a high image quality liquid crystal display is used on the display part 26 of the control part 6, and also the number of sound sources and the capacity of the memory increase, and still also signal processing elements are mounted on the portable terminal and so forth. Particularly, since the current consumption for executing high-function processing becomes large, the consumption of secondary cell serving as a power supply is significant, and there is a likelihood that a call standby time or call time becomes short.
In the area having small number of base station of a new communication system, a call condition is rendered unstable in a week electric field zone. For example, an obstruction such as the inside of the house and so forth brings about call obstruction, which causes an inconvenience such as the limitation of a call zone to a local part such as a location at a window of a building and so forth.
Still further, although the downsizing and low power consumption are achieved if the function of the high-function portable terminal is restricted, such a restriction runs counter to the high-function portable terminal, thereby spoiling the meaning for making the transition to the portable terminal of the new communication system.
Although the portable terminal disclosed in JP-A 2002-9689 realizes an excellent function for dealing with the problem for making the transition to the high-function portable terminal, the foregoing problem is not resolved.